Collapsible drum with reinforced ends

ABSTRACT

The present invention is directed to a collapsible drum for transporting materials. The present invention solves problems associated with reusing and efficiently transporting shipping containers designed for retaining bulk materials, including hazardous substances, and insuring reliable structural integrity with every use. The collapsible drum of the present invention is adapted for integration with standard handling equipment, and has a permanently secured, collapsible drum floor and fluted sidewalls that enable an operator to collapse and roll the empty drum into a compact tube. The collapsible drum provides one or more removable, ribbed disc-shaped inserts for reinforcing the drum floor and/or drum lid.

BACKGROUND

1. Field of the Invention

The present invention relates generally to a collapsible shipping container for transporting bulk materials and more specifically to a reusable collapsible drum with a permanently attached, collapsible bottom panel and at least one selectively removable panel insert for reinforcing the collapsible bottom panel in its expanded state.

2. Discussion of Background information

Plastic and steel drum-style shipping containers commonly retain bulk materials for transportation. These drum containers often transport hazardous liquid and powder materials over long distances without any loss or seepage. Securely retaining hazardous materials in a transport drum is a highly desirable goal, but standard drums present a number of drawbacks that result in inefficiencies, lost profits, injuries and negative environmental impact.

First, standard drums are cumbersome to maneuver. Operators managing these drums typically employ specialized handling equipment designed for engaging these heavy drums and evacuating contents. Once emptied, these standard drums, such as the commonplace 55 gallon steel drum, remain heavy and cumbersome to handle and load onto and off of pallets and shipment trucks. An operator manually moving empty drums and loading them onto a flatbed for shipping to a reconditioning center for example, must move one drum at a time onto a pallet and/or into a truck bed. These heavy 50-60 pound standard 55 gallon drums lack ergonomic handholds and require an operator to execute many repetitive, physically awkward motions to load a fully emptied shipment of drums back onto a truck or shipment pallet. This repetitive movement lacks efficiency and raises the potential for injury every time an operator manually lifts or rolls each ergonomically-challenged drum.

Second, standard shipping drums made of steel, plastic, and aluminum, for example, occupy a significant amount of space during transport, even when the drums are empty. A standard 53 foot flatbed trailer truck can transport only 208 of the standard 55 gallon steel drums. A single standard pallet will hold only about 4 drums. This increases the number of trucks required to ship a large number of drums and thereby increases fuel consumption and harmful emissions associated with the carbon footprint of the shipping vessels.

In addition to causing increased carbon emissions, increased risk of injury and decreased efficiency related to maneuverability, standard drums induce frequent replacement costs because the number of reuses of each drum is limited. Reconditioning a used steel drum, for example, typically requires rinsing and sandblasting the inner surfaces so that all contents are completely removed. These procedures wear the drum walls down and decrease wall thickness, thereby decreasing structural integrity. UN shipping standards require certain minimum wall thicknesses and drum compression strengths for viability. This means that each drum will last through only a few rounds of reconditioning before failing to surpass minimum UN requirements. Standard metal and plastic drums also are susceptible to structural compromise. One dent in a sidewall will create a zone of weakness, lessening the axial compression strength and potentially leading to catastrophic collapse of the drum. Standard steel and plastic drums, therefore, lack resiliency and catastrophically may fail UN compression strength tests after suffering a single indentation.

Some shipping container designs address issues with regard to reuse and compaction during empty transport. These bags and collapsible boxes typically are only semi-rigid at best, tend to bow outward when filled, and are difficult to lift and stack when filled. Their bottoms typically attach to their sidewalls via standing seams that can weaken and separate under the forces applied by container contents. Furthermore, these designs typically fail to integrate with existing drum handling equipment.

A need therefore exists for a reliable, environmentally friendly, highly reusable, fully collapsible rigid drum for use in transporting solid and liquid material governed by the dangerous goods code of the UN regulations. A need exists for such a drum that is designed for integration with existing transportation and handling equipment, wherein the drum is capable of withstanding substantial compression forces without diminishment and capable of collapsing into a compact roll for ergonomic maneuvering and efficient transport when empty. Furthermore a need exists for such a drum having an optional, removable stiffening element for reinforcing a non-rigid, flexible bottom layer of the drum so as to prevent puncture and subsequent leakage of liquid and powered products contained within the drum, wherein the stiffening mechanism, upon removal, collapses with the drum for efficient portage.

SUMMARY OF THE INVENTION

The present invention solves the problems associated with reusing and efficiently transporting shipping containers designed for retaining bulk materials, including hazardous substances, and insuring reliable structural integrity with every use. The collapsible drum of the present invention is adapted for integration with standard handling equipment. The collapsible drum has a permanently secured, collapsible drum floor and fluted sidewalls that enable an operator to collapse and roll the empty drum into a compact tube.

One embodiment of the collapsible drum of the present invention comprises a plurality of vertical ribs for supporting the wall of the drum in an erected state, the plurality of vertical ribs being connected or disconnected along the circumferential plane of the drum. The embodiment further comprises a flexible skin covering the external surfaces of the vertical ribs and a flexible drum floor permanently secured to the flexible skin covering the external surfaces of the ribs. One or more lifting features secure to a pair of diametrically opposed vertical ribs, thereby facilitating lifting of a loaded or partially loaded drum by standard drum handling equipment.

In one embodiment, the plurality of vertical ribs are manufactured from scored fiberboard, and the flexible floor is permanently attached to the flexible skin by fusing the two components together in the plane of the flexible drum floor thereby creating a flat, overlapped, non-standing seam. For example, the seam may be stitched, welded, glued and/or bonded in any permanent, continuous loop disposed on, in and/or through the flexible drum floor.

In one embodiment, the collapsible drum further comprises one or more removable ribbed disc-shaped reinforcement inserts sized and shaped for placement along the bottom of the drum. In one embodiment, the ribbed disc-shaped inserts are formed in the same manner and from the same materials as the collapsible drum such that the ribbed disc-shaped inserts, upon removal, flexibly curl around the collapsed, rolled drum for efficient, compact portage.

BRIEF DESCRIPTION OF THE DRAWINGS

One will better understand these and other features, aspects, and advantages of the present invention following a review of the description, appended claims, and accompanying drawings:

FIG. 1A depicts a side view of one embodiment of the collapsible drum of the present invention.

FIG. 1B depicts a cross sectional top view of one embodiment of the collapsible drum of the present invention.

FIG. 1C depicts a side view of one embodiment of the collapsible drum of the present invention with a cover attached.

FIG. 1D depicts an enlarged partial view of the embodiment of FIG. 1C.

FIG. 1E depicts a perspective bottom view of one embodiment of the collapsible drum of the present invention.

FIG. 2A depicts a cut away cross sectional end view of one embodiment of the collapsible drum of the present invention.

FIG. 2B depicts an enlarged partial view of the embodiment of FIG. 2A.

FIG. 3A depicts a cross sectional, cut away side view of the top end of one embodiment of the collapsible drum of the present invention.

FIG. 3B depicts a cross sectional, cut away side view of the bottom end of one embodiment of the collapsible drum of the present invention prior to attachment of a bottom panel.

FIG. 4 depicts a perspective end view of one embodiment of the collapsible drum of the present invention in a semi-collapsed state.

FIG. 5 depicts the embodiment of FIG. 4 in a further collapsed state.

FIG. 6 depicts a perspective end view of one embodiment of the collapsible drum of the present invention in a fully-collapsed state.

FIG. 7A depicts a front view of one embodiment of a removable ribbed disc-shaped insert of the collapsible drum.

FIG. 7B depicts a perspective view of one embodiment of the removable ribbed disc-shaped insert of FIG. 7A.

FIG. 7C depicts a side view of one embodiment of the removable ribbed disc-shaped insert of FIG. 7A.

FIG. 7D is a blown out, enlarged view of a portion of FIG. 7C.

FIG. 8A depicts a front perspective exploded view of one embodiment of two removable ribbed disc-shaped inserts poised for insertion into the collapsible drum.

FIG. 8B depicts a side view of FIG. 8A.

DETAILED DESCRIPTION

The present invention solves the problems associated with standard drum-style shipping containers.

FIGS. 1A through 1E depict one embodiment of the collapsible drum 100 of the present invention. The drum 100 comprises a plurality of vertical ribs 105 and a permanently attached, flexible bottom panel 107. The plurality of vertical ribs 105 are rigid members that support the wall, or body 110, of the drum 100 in an erected state. Each of the plurality of vertical ribs 105 extends the entire length of the body 110 and preferably has a continuous cross sectional profile throughout its length. This uniform cross sectional profile insures that no weak point exists that would cause a vertical rib 105 to buckle at that localized weak point under the application of forces associated with retaining contents during shipment and handling the drum 100 during stacking, filling and evacuation processes.

As FIGS. 2A and 2B depict, the plurality of vertical ribs 105 may be connected along the circumferential plane 115 of the drum 100. In other embodiments (not shown), the plurality of vertical ribs 105 may be disconnected along the circumferential plane 115 of the drum 100. For example, in a disconnected embodiment, individual loose ribs may be disposed in pockets formed in a unifying tubular sleeve. In such a loose rib embodiment, the pockets and ribs therein would be spaced apart by the semi-rigid sleeve material so that an operator could collapse and roll the drum into a compressed tube, as indicated in the stages of collapse depicted in FIGS. 4 to 6. In yet another disconnected rib embodiment (not shown), individual ribs may be adhered or mechanically bonded to a flexible tubular sleeve such that the individual ribs are spaced apart sufficiently to enable compaction as shown in FIGS. 4 to 6. For example, the ribs may be formed by injection molding flowable plastic into flexible tubular sleeves of woven polypropylene or injected in rib form onto woven polypropylene or any other durable, flexible material capable of withstanding the temperature and pressures associated with an injection mold, such as but not limited to woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. In such an embodiment, the injected plastic will seep through the scrim of the woven fabric, bonding to the threads thereof for secure attachment. Alternate embodiments may comprise a combination of one or more subsets of connected ribs 105 and one or more subsets of disconnected ribs 105.

In all embodiments, the plurality of vertical ribs 105 are preferably evenly spaced with vertical score lines 120, or gaps, therebetween that enable the body 110 to curve into a cylindrical shape. The number and size of vertical ribs 105 varies along with drum size so that all embodiments of the drum 100 take a cylindrical drum shape. As FIGS. 2A and 2B depict, in one embodiment, the plurality of ribs 105 are connected and formed by scoring a single piece of material from both sides to create a symmetrically necked in area 122 at the vertical score line 120. Although not required, this symmetry assists with compressing and rolling the collapsible drum 100 with little resistance. The symmetrically necked in area 122 requires less physical exertion to compress the drum 100 into itself as depicted in FIG. 4 and roll compactly as depicted in FIGS. 5 and 6. If the necked in area 122 were asymmetric so that the material therein were placed more toward the interior or exterior surface of the body 110, resistance forces would increase at those locations thereby impeding bending the body 110 into a rolled shaped. The symmetrical placement of the necked in area 122 allows the plurality of ribs 105 on the inside 505 of rolled drum 100 to compress toward one another during collapse and compaction. The symmetrical placement of the necked in area 122 simultaneously allows the plurality of ribs 105 on the outside 510 of the rolled drum 100 to expand and fan outward. The rolling process thereby produces a compact tube such as that depicted in FIG. 6.

In addition to compressing fiberboard at selective locations to form the plurality of vertical ribs 105, other methods of rib formation exist. In addition to fiberboard, materials of manufacture may include but are not limited to cardboard, high density polyethylene, wood, metal, rigid and flexible composites, fluted plastics, and honeycomb composite. For example, the body 110 of the drum 100 maybe formed of fluted plastic that may be molded, heat formed or extruded to form the plurality of ribs 105. The body 110 may be manufactured from a stamped flexible sheet metal such as aluminum or steel alloy. Any number of methods exist for forming the plurality of ribs 105, but all materials and methods of manufacture produce a body 110 capable of resisting high compression strength while enabling collapse during non-use.

Preferably, the material chosen for the plurality of ribs 105 is lightweight and resistant to both longitudinal and radial compression and expansion forces. Fiberboard, for example, is significantly lighter than steel and exhibits high compression strength in an axial direction. A stack load test conducted on an embodiment the drum 100 of present invention resulted in withstanding 7000 pounds of force without any indication of radial expansion or buckling. The tested embodiment was manufactured from platen pressed fiberboard comprising one and one half inch wide, interconnected ribs 105 wrapped in woven polypropylene and lined inside with four (4) mil woven polyethylene. This trial comprised more strenuous test conditions than those required by UN shipping regulations which require dropping each of six equally sized drums only once for each test. A single 22″ diameter, 34″ high drum of the fiberboard embodiment of the present invention, dropped sixes times repeatedly from 1.8 meters, continued exhibiting the 7000 lbf compression load strength results. A standard steel drum of similar dimensions typically withstands only 1200 pounds of force under the less strict UN testing requirements.

Returning to the embodiment of pressed fiberboard, as the cross sectional views of FIGS. 2A and 2B depict, the compressed material located in the neck in area 122 at the vertical score line 120 and connecting adjacent ribs 105 is centered between the inner and outer surfaces of the plurality of ribs 105. The neck in area 122 at the vertical score line 120 comprises material compressed to a thickness τ that is least half the overall cross sectional thickness T of each of the plurality of ribs 105 and more preferably at least a third of the overall thickness T of each of the plurality of ribs 105. In some embodiments, the neck in area 122 may be compressed so as to be completely planar and sheet-like in thickness τ. Using a driven platen or rotary press and a compressible material, such as fiberboard, to form the plurality of ribs 105 enables accurate and efficient production of a drum body 110 having highly compressed material at the neck in area 122 along each of the vertical score lines 120.

The out press ridges impact the fiberboard and simultaneously produce the vertical score lines 120 and the plurality of ribs 105 therebetween. The press ridges therefore may be sized so that the vertical score lines 120 have a desired width ω. Wider score lines 120 (i.e. wider gaps between the plurality of ribs 105) may be preferable for enabling compression and compaction of a large drum 100 and/or a body 110 having wide ribs 105. The platen press ridges also may be spaced apart at particular intervals to produce ribs 105 of desired width W. The plurality of ribs 105 may be equally sized or may comprise ribs 105 of two or more varying widths W, W′.

As with selecting the width w of the vertical score lines 120, selecting the spacing between the platen ridges and thereby determining the width W of each of the plurality ribs 105 may depend on the overall dimensions of the collapsible drum 100. For example, a ratio of rib width W to drum diameter D may be between 11:1 and 36:1 and more preferably may be between 17:1 and 25:1. A ratio of 22:1 enables easy compaction and tight rolling of a drum having standard drum dimensions of approximately 22 inches in diameter and 34 inches in height while producing compression strength results described in the above trial. In such an embodiment, trials indicated that a compressible drum 100 with these standard dimensions rolled up into itself more compactly and with less exertion when each of the plurality of ribs 105 was one inch wide instead of two inches wide.

Returning now to FIGS. 2A and 2B, whether the plurality of ribs 105 are partially or wholly connected and/or disconnected, embodiments of the collapsible drum 100 further comprise a flexible skin 125. FIGS. 2A and 2B depict one embodiment wherein the plurality of ribs 105 are connected and encapsulated by a flexible skin 125. The flexible skin 125 protects the plurality of ribs 105 from damage from the elements and damage associated with shipping and handling. Additionally, the flexible skin 125 assists the body 110 with resisting radial forces and preventing bulging during use, shipping and handling. The flexible skin 125 may be a material such as, but not limited to, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. Preferably the material comprising the flexible skin has a low modulus of elasticity and therefore contributes to the high bulk modulus of the collapsible drum 100 of the present invention. The fibers of the flexible skin 125 preferably exhibit high shear strength so as to withstand radial and axial compression forces both under load and under compression while the flexible skin 125 remains supple enough to avoid fiber degradation and shear strength degradation after repeated compaction and rolling of the drum. For example, a flexible skin 125 comprising woven polypropylene counteracts radial expansion forces and produces the above described trial results in the described fiberboard embodiment of the collapsible drum 100 of the present invention.

The flexible skin 125 may be permanently disposed on the body 110 of the drum 100 using a method such as but not limited to gluing, epoxying, welding, injection molding, and shrink wrapping. One embodiment of a method of manufacturing the drum 100 comprises applying a flexible skin 125 to fiberboard prior to press formation of the plurality of ribs 105 and vertical score lines 120. This insures that the flexible skin contours the ribs 105 and vertical score lines 120 and thereby further assists with withstanding radial expansion forces acting on the body 110 during periods of use and enabling efficient collapse and rolling of the drum 100 during periods of non use.

In one embodiment depicted in the cut away cross sectional views of FIGS. 3A and 3B, the drum 100 further comprises an inner lamination layer 130 applied to the interior surfaces of the plurality of ribs 105. In the embodiment shown, the inner lamination layer 130 overlaps the end of the plurality of ribs 105 and adheres to the outer surface of the body 110. The inner lamination layer permanently affixes to the body 110 through means such as but not limited to gluing, epoxying, welding, injection molding, and shrink wrapping. Furthermore, the inner lamination layer 130 may be comprised of a material such as, but not limited to, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. In one embodiment, the inner lamination layer 130 is made of polyethylene and/or polyethylene film and thereby provides a clean surface against which an optional disposable inner receptacle, i.e. a liner, may slide during installation and removal.

As FIGS. 3A and 3B depict, embodiments of manufacturing the collapsible drum 100 may comprise applying the inner lamination layer 130 prior to applying the flexible skin 125. In the embodiment of FIGS. 3A and 3B, the drum 100 comprises a flexible skin 125 applied to the outside of the plurality of ribs 105 comprising the body 110 and disposed on the folded over portion of the inner lamination layer 130 so that the flexible skin overlaps the inner lamination layer 130 on the inside surface of the plurality of ribs 105 comprising the body 110. This overlapped configuration produces a secure bond between the flexible skin 125 and inner lamination layer 130 and thoroughly contributes the protecting of the ends of the plurality of ribs 105 from environmental and materials damage. The combination of overlapped flexible skin 125 and inner lamination layer 130 further contributes to the high bulk modulus of the drum 100.

As FIG. 3B depicts, one embodiment of a method of manufacturing the collapsible drum 100 of the present invention comprises permanently attaching the flexible drum floor 107 to the flexible skin 125. The flexible drum floor 107 of the present invention affixes to the body of the drum 110 at an overlapping horizontal seam between the flexible skin 125 and the flexible drum floor 107. Like the flexible skin, the drum floor 107 is made from a flexible but strong material. Because the drum floor 107 is flexible, an operator may collapse and roll the drum 100 without having to remove the drum floor 107. The drum floor 107 material remains supple and compressible while retaining a low modulus of elasticity. For example, the flexible floor 107 may be a material such as, but not limited to, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. Preferably the material comprising the flexible skin has a low modulus of elasticity and therefore contributes to the high bulk modulus of the collapsible drum 100 of the present invention. The fibers of the flexible floor 107 preferably exhibit high shear strength so as to withstand radial and axial compression forces both under load and under compression while the flexible floor 107 remains supple enough to avoid fiber degradation and shear strength degradation after repeated compaction and rolling of the drum. For example, a flexible floor 107 comprising woven polypropylene counteracts radial expansion forces and produces the above described trial results in the described fiberboard embodiment of the collapsible drum 100 of the present invention.

As the embodiment in FIG. 1E depicts, the flexible drum floor 107 is permanently secured to the body 110 in a manner that eliminates the need for a standing seam. Standard drums and bulk bags typically comprise a floor attached to the sidewalls at a standing seam. Methods of manufacturing such existing drums are far more simplistic when the floor attaches at an easily manipulated standing seam. In such drums, the bottom panel often separates from the sidewall(s) at the point of attachment when drum contents induce radial and axial expansion forces. In contrast, the collapsible drum 100 of the present invention solves this problem associated with standing seams and provides a highly secure method of attachment that enables repeated reuse of the drum 100 without concern of catastrophic failure. As FIG. 3B depicts, the flexible skin 125 applied to the outside surface of the body 110 extends beyond the lower ends of the plurality of ribs 105 to form a free-hanging bottom margin 135. The free-hanging bottom margin 135 then folds inward along the radius of the drum 100 (i.e. at an angle of 90 degrees from the body) and in the direction of arrow 140 so that the free hanging bottom margin 135 lies parallel to the plane of the flexible drum floor 107. The flexible drum floor 107 is then disposed on the free hanging bottom margin 135 so that the flexible drum floor 107 and circumferential free-hanging bottom margin 135 overlap. Accordingly, the flexible drum floor 107 is permanently attached to the bottom margin 135 through a permanent bonding means applied in the plane of the drum floor 107.

In one embodiment depicted in FIG. 1E, the two layers are stitched together in a continuous circumferential loop 109 in the plane of the flexible drum floor 107. In other embodiments, the drum floor 107 may be permanently attached to the bottom margin 135 by any number of affixation methods including by not limited to stitching, welding, heat fusing, stapling, and epoxy bonding. Regardless of the method of attachment, in all embodiments, the two layers are affixed in a continuous circumferential loop in the plane of the flexible drum floor 107 so that the drum floor 107 stays securely and permanently affixed to the body 110. Because the drum floor and bottom margin 135 are bonded in the plane of the drum floor 107, rather than at a vertical standing seam around the periphery of the drum 100, no separation risk exists when the drum 100 is in use. Furthermore, in some embodiments, the drum floor 107 may comprise two layers such that the bottom margin 135 is sandwiched between the two layers of the drum floor 107 prior to bonding the drum floor 107 to the bottom margin 135. This configuration strengthens the bond between the bottom margin 135 and the drum floor 107 and further protects the bottom margin 135 from fraying and potentially detaching from the drum floor 107.

Additionally, a retaining feature (not shown) may be disposed on the inner surface of the drum floor 107 for retaining a disposable liner (not shown) within the drum 100. For example, in one embodiment the retaining feature may be a Velcro® system, with a sizeable Velcro® panel secured to the inside surface of the drum floor 107 and a mating Velcro® portion secured to the liner. Securing at least one Velcro® panel on at least a third of the inner surface of the drum floor 107 enables retention of the disposable liner during contents evacuation. As one of skill in the art will recognize, other retention systems are capable of producing the same result such as but not limited to snaps, zippers, hook and latch, tie downs, and static charge. Such liners enable transport of hazardous and/or liquid materials without degrading the components of the collapsible drum and thereby increase the potential number of reuses of a drum.

Because the collapsible drum 100 of the present invention is designed for industrial use, further reinforcement of the drum floor 107 is desirable during transport of liquid or powdered materials that could seep out if the drum floor 107 were ruptured or punctured. Because the drum floor 107 is typically made from a collapsible fabric as described above, punctures are conceivable during industrial handling. Reinforcing the drum floor 107 with one or more stiff, removable ribbed disc-shaped inserts 600 eliminates the risk of puncturing the drum floor 107 and/or the disposable liner and adds rigidity to the erected drum 100.

As shown in FIGS. 7A through 8B, one embodiment of the disc-shaped insert comprises a plurality of parallel ribs 605. The disc-shaped insert 600 may be manufactured in the same variety of ways and from the same materials described in reference to the body 110 of the collapsible drum 100. For example, in one embodiment, the disc-shaped insert 600 may be manufactured from pressed fiberboard laminated with one or more woven fiber materials, such as but not limited to, woven polyurethane, reinforced polyethylene, woven fiberglass, and other polymeric materials. This low cost, efficient manufacturing process is described above with regard to the formation of the vertical ribs 105 of the collapsible drum 100. As with the vertical ribs 105 of the collapsible drum 100, the parallel ribs 605 of one embodiment of the disc-shaped insert 600 may be formed by scoring fiberboard from both the top and bottom planar surfaces of the insert 600.

Additionally, the laminated outer layer may be a comprised of one or more sections applied to one or both surfaces of the insert 600. For example, in one embodiment, a first layer of woven polyurethane is applied to the top surface of the insert and folded over and adhered onto the bottom surface. A second layer of woven polyurethane is applied to the bottom surface and folded over and adhered to the top surface of the insert 600, atop the first layer of woven polyurethane. Other embodiments may include, for example, heat welding a top layer and bottom layer together along the circumferential edge of the insert 600 or overlapping and adhering the two layers along the circumferential edge. In all embodiments, preferably the laminated out layer comprises no raised seam along the circumferential edge, thereby aiding in the ease of insertion and removal of the insert 600 into and out of the collapsible drum 100.

Turning now to the completed construction of the insert 600, as the side view of FIG. 7C and blown out view 7D depict, the material of the insert 600 located in the neck in area 622 at the disc rib score line 620 and connecting adjacent ribs 605 is centered between the top and bottom surfaces of the plurality of parallel ribs 605. The neck in area 622 at the disc rib score line 620 comprises material having a thickness t′ that is at least half the overall cross sectional thickness T′ of each of the plurality of parallel ribs 605 and more preferably at least a third of the overall thickness T′ of each of the plurality of parallel ribs 605. In some embodiments, the neck in area 622 may be completely planar and sheet-like in thickness t′.

In one embodiment, using a driven platen or rotary press and a compressible material, such as fiberboard, to form the plurality of parallel ribs 605 enables accurate and efficient production of a ribbed disc-shaped insert 600 having highly compressed material at the neck in area 622 along each disc rib score line 620. The out press ridges impact the fiberboard and simultaneously produce the disc rib score lines 620 and the plurality of parallel ribs 605 therebetween. The press ridges therefore may be sized so that the disc rib score lines 620 have a desired width w′. Wider score lines 620 (i.e. wider gaps between the plurality of parallel ribs 605) may be preferable for enabling compression and compaction along with a collapsible large drum 100 and/or a body 110 having wide vertical ribs 105. The platen press ridges also may be spaced apart at particular intervals to produce parallel ribs 605 of desired width W′. In one embodiment, W″ is smaller than width W associated with the drum body 110, and the ribbed disc-shaped insert 600 therefore comprises a plurality of parallel ribs 605 that are narrower than the plurality of vertical ribs 105 of the body 110 (i.e. more parallel ribs 605 per inch on the disc-shaped insert 600 than vertical ribs 105 per inch on the drum body 110). This is advantageous at least for providing more flexibility in curling a removed insert 600 around and along the exterior of the rolled drum 100 in its collapsed and compacted state.

The one or more ribbed disc-shaped inserts 600 therefore are designed for insertion into the drum during use and for collapsing with the drum during rolling and compaction. As indicated in FIGS. 8A and 8A, in one embodiment, the one or more ribbed disc-shaped inserts 600 are sized so that the diameter of each insert 600 is slightly shorter than the diameter D of the drum 100. The one or more ribbed disc-shaped inserts 600 therefore, in one embodiment, contact the inner surface of the drum body 110, enabling the one or more disc-shaped inserts 600 to self center during insertion. Because a disc-shaped insert 600 overlies the inside surface of the drum floor 107, in one embodiment, the non-permanent attachment means, such as Velcro®, for retaining a disposable liner may be located along the inner surface of the body 110 in one or more locations. Furthermore, in one embodiment the one or more disc-shaped inserts may further comprise non-permanent attachment means, such as Velcro® for secure attachment to the inside surface of the drum floor 107. In an embodiment having at least two disc shaped inserts, the bottom insert 600 further may comprise secure but non-permanent attachment means, such as Velcro®, on a top surface for mating with a corresponding attachment means on the bottom surface of the top insert 600.

The plurality of disc ribs 605 of the one or more inserts 600 therefore align parallel with the diameter of the drum 100, and therefore stiffen the plane of the flexible drum floor 107. The insert 600 forms a barrier between external elements, such as pallets, forklifts and other industrial handling equipment, and the contents of the drum 100. Additionally, the plurality of disc ribs 605 add compression strength along the longitudinal length of the ribs 605 and thereby assist with expanding and holding the erected drum 100 in a full drum shape when first unrolled and opened. Introducing more than one insert 600 further augments all of these advantages. For example, as indicated in FIGS. 8A and 8B, adding two inserts with their disc ribs 605 aligned at a non-parallel angle relative to each other stiffens the flexible floor 107 and the body 110 so that the drum 100 holds its cylindrical shape and so that contents therein are protected from external forces. These external forces could be, for example, industrial handling equipment that could improperly or roughly engage the drum 100 and puncture the drum floor 107 and any liners within the drum, thereby allowing the contents to evacuate undesirably.

Furthermore, aligning the two inserts 600 so that the axes of their ribs are at a non-parallel angle relative to one another assists the drum 100 in holding its cylindrical shape, particularly immediately following expansion of the drum from a collapsed state. During the expansion process the drum 100 may present kinks imparted during collapse and compaction, and the disc-shaped inserts 600 impart stiffness to the drum body 110 and assist with opening the cylindrical drum 100 to a fully cylindrical cross sectional shape.

In one embodiment, the top rim of the drum 100 further comprises markings for aligning the axes of the ribs of two disc shaped inserts 600 so that the disc ribs 605 of one insert 600 form an angle relative to the disc ribs 605 of the other insert. In one embodiment, that angle is greater than 0 degrees and less than 180 degrees. Preferably, in one embodiment, the axes of the ribs 605 of one disc-shaped insert 600 are at an angle at or between 30 and 150 degrees relative to the axes of the ribs 605 of the second disc-shaped insert 600. In one embodiment, the axes of the ribs 605 of one disc-shaped insert 600 are at an angle of 90 degrees relative to the axes of the ribs 605 of the second disc-shaped insert 600, and the rim of the drum 100 is marked accordingly for aligning the axis of the central rib 605 of each of the two disc shaped inserts 600. For example, the rim of the drum 100 may be marked with two diametrically opposed red dots for aligning the ends of a central rib 605 of a first disc shaped insert 600 and two diametrically opposed yellow dots for aligning a central rib 605 of a second disc shaped insert, where a vector between the two red dots is positioned at a 90 degree angle to a vector between the two yellow dots. Aligning the two disc shaped inserts 600 so that axes of their respective ribs form an angle of 90 degrees increases resistance of the drum wall to radial compression forces especially applied at or near the drum floor, such as, for example, forces applied by a misaligned forklift

Additionally, in one embodiment, a disc shaped insert 600 is inserted into the lid 160 of the drum and held in place via frictional forces and/or non-permanent attachment means such as a two-part Velcro® system. Adding an insert to the lid 160, especially a flexible lid 160 made of a woven material such as woven polypropylene, assists with protecting that flexible member and provides an additional barrier against puncture by external elements.

Furthermore, in some embodiments, the at least one disc-shaped insert 600 inserted into the drum 100 and any additional disc-shaped inserts 600 inserted into the drum 100 and/or lid 160, further comprise means for easily grasping and removing the one or more inserts 600. For example, the one or more disc-shaped inserts 600 may comprise one or more loops of material applied to an accessible surface for grasping and pulling the one or more inserts free of the drum 100 and/or lid 160. The one or more loops may be made of the same material as the outer lamination layer and may be applied by techniques such as, but not limited to stitching, welding, gluing, epoxying, heat welding, stapling and riveting. In this embodiment, removing an insert 600 from the drum 100, for example, simply requires grasping the loop with one or more fingers and pulling upward until the insert is free of the drum 100. Following removal of the insert 600 and compaction of the drum 100, the insert 600 folds around the compacted drum 100 and may be secured thereto with a non-permanent attachment means such as, for example a lace, tie, Velcro® strap, ratchet strap, etc. In another embodiment, the insert 600 is left in the drum 100, but pulled upward so that the insert 600 lies along and contours to the inner surface of the body 110. The raised disc-shaped insert 600 then is compacted with the drum 100 during the compaction process discussed hererin with regard to FIGS. 4 through 6. In any embodiment, storing the one or more inserts 600 adjacent to and contoured with the collapsed drum 100 saves space and assists with porting the elements in a tidy, unified package.

Turning now to the exterior of the drum 100, the present invention is designed for full integration with existing handling equipment designed for maneuvering standard, non collapsible shipping drums. Most notably, the collapsible drum 100 of the present invention comprises one or more lifting features 145 secured to a pair of diametrically opposed vertical ribs 105. The lifting features 145 enable handling equipment to securely grasp the drum 100 during lifting and evacuation processes without the drum sliding free of the handling equipment. The lifting features 145 thereby facilitate lifting a loaded or partially loaded drum 100 with drum handling equipment. In some embodiments, lifting features 145 may be disposed on more than two of the plurality of ribs 105 so as to avoid limiting the directionality of the handling equipment when engaging the drum 100. Selecting the number and placement of lifting features 145 depends in part on the volume of the lifting features 145 and how tightly the drum 100 needs to collapse and roll for efficient handling and shipment during periods of non-use.

In one embodiment depicted in FIG. 2B, the lifting features 145 are rectangular shaped blocks mechanically fastened to the outside of the drum 100 by a mechanical fastening means 150. The lifting features 145 may be manufactured from a light weight, solid material such as but not limited to wood, plastic, metal and epoxy impregnated fiberglass. The mechanical fastening means 150 are any known fastening devices such as but not limited to rivets, screws, nails, glue, welds, and clamps. In the embodiment of FIGS. 2A and 2B, the mechanical fastening means 150 secure the lifting features 145 to a clamping plate 155 wound within the flexible skin 145 and spaced apart from the plurality of ribs 105. In this embodiment, the mechanical fastening means 150 pierce only the clamping plate 155 without potentially compromising the structural integrity of the rib 105 therebeneath.

In other embodiments, the mechanical fasteners 155 attach directly to a rib 105 by first puncturing the flexible skin 125. In these embodiments, the rib 105 to which a mechanical fastener attaches has a higher shear strength than the remainder of the plurality of vertical ribs 105 so that attaching the lifting features 145 does not decrease compression strength and bulk modulus of the overall drum 100. In some embodiments, these ribs 105 to which mechanical fasteners 155 apply are wider and/or thicker than the remainder of the plurality of ribs 105. In some embodiments, the ribs 105 to which mechanical fasteners 155 apply may be formed integrally with the remainder of the plurality of ribs 105 or they may be added later as independent panels of the same or different material of manufacture. In the case of independent ribs 105 being added for support of lifting features 145, those independent ribs 105 may be joined to the remainder of the plurality of ribs 105 by a fastening mechanism such as but not limited to tape, screws, adhesive, pegs, rivets, and nails. Alternatively, the flexible skin 125 and/or inner lamination layer 130 may hold independent ribs 105 in alignment with adjacent ribs 105.

In addition to lifting features 145, embodiments of the drum 100 of the present invention also comprise an integrated fabric lid 160. The lid 160 may be made of any flexible, durable material capable of collapsing with the drum 100 during storage and providing a barrier between drum contents and the external environment. The flexible material may be, but is not limited to, woven polyurethane, reinforced polyethylene, woven fiberglass, or polymeric material. The lid may be fully detachable or partially attached in a permanently or semi-permanently manner so as to insure lid retention and ready availability. In one embodiment depicted in FIGS. 1A, 1C and 1D, the lid 160 is semi-permanently attached through a buckle closure 165 extending between the lid and the outside of the drum 100. Other means of attachment may include but are not limited to Velcro®, snaps, zippers, and tie downs. Additionally, in some embodiments, the portion of the lid 160 extending over the outside surface of the drum 100 further may comprise an elastic tension element integrated therein for securely attaching the lid 160 to the drum 100. In further embodiments, the lid 160 may be solid or may comprise a solid feature for forming a hermetic seal around the drum 100 and/or the liner therein.

The spaced rib configuration of the present invention enables an operator to collapse the drum into a sea-shell shape as indicated in FIG. 4, and roll the drum 100 into a compact tube as indicated in the stages of rolling depicted in FIGS. 5 and 6. Some embodiments of the drum of the present invention may include a latch system 500, such as a two-piece Velcro® hook and loop stay, for maintaining the drum 100 in a collapsed and compactly rolled state. Compacting a standard sized collapsible drum 100 (i.e. 22 inch diameter, 34 inches high) enables an operator to lift and maneuver the drum 100 without any exertion and without requiring any specialized handling equipment. Furthermore, a pallet typically holds only four(4) similarly sized fifty to fifty-five (50-55) gallon shipping drums, which limits a standard 53 foot flatbed trailer to transporting only about 208 empty conventional drums. In comparison, a 53 foot flatbed trailer can transport approximately eighteen hundred and seventy-two (1872) collapsible drums 100 of the present invention in their rolled state that enables the placement of thirty-six(36) units per shipment skid. This reduces diesel usage and thereby lessens the carbon footprint associated with the reuse market and shipment of empty drums. Compaction of the collapsible drums 100 of the present invention also decreases the required labor associated unloading pallets and/or boxes of typical standard 50-55 gallon drums.

It is noted that the foregoing examples have been provided merely for the purpose of explanation and are in no way to be construed as limiting of the present invention. While the present invention has been described with reference to an exemplary embodiment, it is understood that the words, which have been used herein, are words of description and illustration, rather than words of limitation. Changes may be made, within the purview of the appended claims, as presently stated and as amended, without departing from the scope and spirit of the present invention in its aspects. Although the present invention has been described herein with reference to particular means, materials and embodiments, the present invention is not intended to be limited to the particulars disclosed herein; rather, the present invention extends to all functionally equivalent structures, methods and uses, such as are within the scope of the appended claims. 

1) A collapsible drum for handling materials, the collapsible drum comprising: a) a plurality of vertical ribs for supporting the wall of the drum in an erected state, the plurality of vertical ribs being connected or disconnected along the circumferential plane of the drum; b) a flexible skin covering the external surfaces of the vertical ribs; c) a flexible drum floor permanently secured to the flexible skin covering the external surfaces of the ribs; d) one or more lifting features secured to a pair of diametrically opposed vertical ribs thereby facilitating lifting of a loaded or partially loaded drum by drum handling equipment; and e) one or more removable ribbed disc-shaped reinforcement inserts layered upon the inside surface of the flexible drum floor such that the planar surfaces of the one or more removable disc-shaped reinforcement inserts are parallel to the drum floor and such that the entire circumferential edge of each of the one or more ribbed disc-shaped reinforcement insert is adjacent the inner surface of the wall of the drum in an erected state. 2) The collapsible drum of claim 1 wherein the pair of diametrically opposed vertical ribs having one or more lifting features thereon have higher shear strength than the remainder of the plurality of vertical ribs. 3) The collapsible drum of claim 1 wherein at least a subset of the vertical ribs is connected along the circumferential plane of the drum and this subset of ribs is produced from rigid fiberboard scored to form the ribs. 4) The collapsible drum of claim 3 wherein the rigid fiberboard is scored evenly from both sides and to the same depth on both sides so that the compressed portion of the fiberboard is centered between the inner and outer surfaces of vertical ribs. 5) The collapsible drum of claim 1 wherein at least a subset of the vertical ribs is connected along the circumferential plane of the drum and this subset of ribs is produced by extrusion. 6) The collapsible drum of claim 1, wherein at least a subset of the vertical ribs is connected along the circumferential plane of the drum and this subset of ribs is produced by injection molding onto the flexible skin. 7) The collapsible drum of claim 1 wherein at least a subset of the vertical ribs is connected along the circumferential plane of the drum and this subset of ribs is produced by pressing a deformable rigid material. 8) The collapsible drum of claim 1, further comprising an inner lamination layer disposed on the internal surfaces of the plurality of vertical ribs and overlapping the top edges and bottom edges of the plurality of vertical ribs to adhere to the external surfaces of the plurality of vertical ribs. 9) The collapsible drum of claim 8 wherein the flexible skin covering the external surfaces of the vertical ribs overlaps the top edges of the plurality of vertical ribs to securely adhere to the inner lamination layer and extends beyond the bottom edges of the plurality of vertical panels to create a free-hanging bottom margin. 10) The collapsible drum of claim 9 wherein the free-hanging bottom margin of the flexible skin covering the external surfaces of the vertical ribs folds inward along the radius of the drum to lie parallel to the flexible drum floor during mating. 11) The collapsible drum of claim 10 wherein the flexible drum floor is permanently attached to the bottom margin by stitching the two layers together in a continuous circumferential loop in the plane of the flexible drum floor. 12) The collapsible drum of claim 10 wherein the flexible drum floor is permanently attached to the bottom margin by welding the two layers together in a continuous circumferential loop in the plane of the flexible drum floor. 13) The collapsible drum of claim 10 wherein the flexible drum floor further comprises at least two parallel layers and wherein the bottom margin of the flexible skin covering the external surfaces of the vertical ribs is sandwiched between the two parallel layers prior to mating. 14) The collapsible drum of claim 1 wherein the flexible drum floor is made of the same material as the flexible skin covering the external surfaces of the vertical ribs. 15) The collapsible container of claim 1 wherein the flexible drum floor is manufactured from a non-rigid woven material with a low modulus of elasticity. 16) The collapsible drum of claim 1 wherein the flexible drum floor is manufactured from a material chosen from the group consisting of woven polyurethane, reinforced polyethylene, woven fiberglass, and polymeric material. 17) The collapsible drum of claim 1 wherein the inner lamination layer is manufactured from a material chosen from the group consisting of woven polyurethane, reinforced polyethylene, woven fiberglass, and polymeric material. 18) The collapsible drum of claim 1 wherein the flexible skin covering the external surfaces of the vertical ribs is manufactured from a material chosen from the group consisting of woven polyurethane, reinforced polyethylene, woven fiberglass and polymeric material. 19) The collapsible drum of claim 1 wherein the a plurality of vertical ribs are made from a material chosen from the group consisting of fiberboard, cardboard, high density polyethylene, wood, metal, composite and polymeric material 20) The collapsible drum of claim 1, further comprising a retaining element secured to the inner surface of the flexible drum floor for retaining a disposable liner disposed within the containment cavity. 21) The collapsible drum of claim 20 wherein the retaining element is Velcro® and a mating Velcro® portion is attached to an outer surface of the disposable liner. 22) The collapsible drum of claim 1 wherein the one or more ribbed disc-shaped reinforcement inserts further comprise an outer skin layer. 23) The collapsible drum of claim 22 wherein the outer skin layer is adhered to the outer surfaces of the one or more disc-shaped reinforcement inserts. 24) The collapsible drum of claim 22 wherein the outer skin layer is shrink wrapped around the one or more disc-shaped reinforcement inserts. 25) The collapsible drum of claim 22 wherein the one or more disc-shaped reinforcement inserts are injection molded onto the outer skin layer. 26) The collapsible drum of claim 22 wherein the outer skin layer is manufactured from a material chosen from the group consisting of woven polyurethane, reinforced polyethylene, woven fiberglass, and polymeric material. 27) The collapsible drum of claim 1 wherein at least a subset of the ribs of the one or more disc-shaped reinforcement inserts are parallel and connected, and wherein this subset of ribs is produced from rigid fiberboard scored to form the ribs. 28) The collapsible drum of claim 27 wherein the rigid fiberboard is scored evenly from both sides and to the same depth on both sides so that the compressed portion of the fiberboard is centered between the top and bottom surfaces of the ribs. 29) The collapsible drum of claim 1 wherein at least a subset of the ribs of the one or more disc-shaped reinforcement inserts are parallel and connected, and wherein this subset of ribs is produced by extrusion. 30) The collapsible drum of claim 1 wherein at least a subset of the ribs of the one or more disc-shaped reinforcement inserts are parallel and connected, and wherein this subset of ribs is produced by pressing a deformable rigid material. 31) The collapsible drum of claim 1, further comprising two ribbed disc-shaped reinforcement inserts wherein the ribs on each insert are parallel. 32) The collapsible drum of claim 31 wherein the two ribbed disc-shaped inserts are inserted into the drum such that the parallel ribs of one ribbed disc-shaped insert are aligned at an angle between 0 and 180 degrees relative to the parallel ribs of the other ribbed disc-shaped reinforcement insert. 33) The collapsible drum of claim 31 wherein the two ribbed disc-shaped inserts are inserted into the drum such that the parallel ribs of one ribbed disc-shaped insert are aligned at an angle at or between 30 and 150 degrees relative to the parallel ribs of the other ribbed disc-shaped reinforcement insert. 34) The collapsible drum of claim 31 wherein the two ribbed disc-shaped inserts are inserted into the drum such that the parallel ribs of one ribbed disc-shaped insert are aligned at an angle of 90 degrees relative to the parallel ribs of the other ribbed disc-shaped reinforcement insert. 35) The collapsible drum of claim 1 further comprising an integrated lid attached to the collapsible drum and manufactured from a flexible material. 36) The collapsible drum of claim 35 wherein the flexible material is a material chosen from the group consisting of woven polyurethane, reinforced polyethylene, woven fiberglass, and polymeric material. 37) The collapsible drum of claim 35 further comprising a buckle closure extending between the integrated lid and the external surface of the collapsible drum. 38) The collapsible drum of claim 35 further comprising Velcro® extending between the integrated lid and the external surface of the collapsible drum. 39) The collapsible drum of claim 35 further comprising one or more snaps extending between the integrated lid and the external surface of the collapsible drum. 40) The collapsible drum of claim 35 further comprising one or more ties extending between the integrated lid and the external surface of the collapsible drum. 41) The collapsible drum of claim 35 further comprising a ribbed disc-shaped insert disposed on and parallel to an inside surface of the integrated lid. 